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Toxoplasma gondii & Human Phenotype

Compendium of Known Effects and Ongoing Research

sex ratio

An elevated blood glucose level and increased incidence of gestational diabetes mellitus in pregnant women with latent toxoplasmosis

September 27, 2015
Kaňková, Š., Flegr, J., Calda, P.
Folia Parasitologica 2015; 62: 041doi: 10.14411/fp.2015.041
Click for abstract
About 30–50% of the world human population are infected with the protozoan parasite Toxoplasma gondii ( Nicolle et Manceaux, 1908). Latent toxoplasmosis has many specific behavioural and physiological effects on the human body and influences the course of pregnancy, including secondary sex ratio of children of infected mothers. It was suggested that an increased concentration of glucose could be the proximate cause of increased sex ratio. There are some indirect indications of possible association between toxoplasmosis and certain forms of diabetes. Here we searched for a possible link between latent toxoplasmosis and the level of glu - cose in the blood. In a cross-sectional study, we found that pregnant women with latent toxoplasmosis had significantly higher blood glucose levels during the oral glucose tolerance test (n = 191, p = 0.010; the level of fasting plasma glucose: mean = 5.04 mmol/l vs mean = 4.88 mmol/l; blood glucose level at 1 hour mean = 7.73 mmol/l vs mean = 6.89 mmol/l and blood glucose level at two hours mean = 6.43 mmol/l vs mean = 5.74 mmol/l) and higher prevalence (19.5 %) of gestational diabetes mellitus (n = 532, p = 0.033, odds ratio = 1.78) in the 24–28th gestational weeks than T. gondii- free women (12.0 %). Increased level of glucose and increased incidence of gestational diabetes mellitus could have considerable clinical impact as contributors to the development of the metabolic syndrome and type 2 diabetes in T. gondii -infected women. Our results also brought the first empirical support for the hypothesis that the glucose concentration may play a role in T. gondii -associated offspring sex ratio shifts

Tagged: GDM, oral glucose tolerance test, Parasite, risk factors, sex ratio, Toxoplasma gondii

Physical health

The influence of latent toxoplasmosis on women’s reproductive function: four cross-sectional studies

January 8, 2015
Kankova, S., Flegr, J., Calda, P.
Folia Parasitologica 2015; 62:
Click for abstract
Several studies have investigated the association between infection with Toxoplasma gondii (Nicolle et Manceaux, 1908), pregnancy and fertility, but the results of studies focused on the fertility are rather ambiguous. Here we report results of four new cross-sectional studies. The studies were performed in the General University Hospital, Prague (study A with n = 1 165, and study C with n = 317), in private clinics of the Centre of Reproductive Medicine, Prague (study B with n = 1 016), and in a population of Czech and Slovak volunteers from the Facebook page 'Guinea Pigs' willing to participate in various basic science studies (study D with n = 524). In studies A and B, the clinical records were used to assess the fertility problems, whereas in studies C and D, the women were asked to rate their fertility problems using a six-point scale. Pregnant T. gondii-infected women were older than T. gondii-free women (study A: 33.1 vs 31.2, P < 0.001; study B: 30.6 vs 29.6, P = 0.012) and more often used assisted reproductive technology to conceive (study A: 17.2% vs 12.4%, P = 0.041; study B: 13.4% vs 9.2%, P = 0.317). Pregnant T. gondii-infected primiparous women were older than T. gondii-free primiparas (study A: 31.1 vs 29.5, P < 0.001; study B: 29.7 vs 28.9, P = 0.064) and more often used assisted reproductive technology to conceive (study A: 24.7% vs 14.4%, P = 0.010; study B: 15.9% vs 15.5%, P = 0.888). T. gondii-infected women reported to take a longer time to conceive than T. gondii-free women (P = 0.015). They also claimed to have more fertility problems than T. gondii-free women (P < 0.0001). Our results suggest that 'asymptomatic' latent toxoplasmosis could be a more serious source of fertility problems and health-associated burden than more severe but far rarer congenital toxoplasmosis.

Tagged: age, asymptomatic toxoplasmosis, behavioral-changes, gender differences, gondii, hypothesis, infertility, manipulation hypothesis, mice, Parasite, psychiatric-disorders, Schizophrenia, sex ratio, testosterone, Toxoplasma gondii

Reproduction

Are there any relationships between latent Toxoplasma gondii infection, testosterone evelatin, and risk of autism spectrum disorder?

October 9, 2014
Abdoli A, Dalimi A.
Frontiers in Behavioral Neuroscience 2014; 8
Tagged: 4th digit ratio, autism, bipolar disorder, dopamine function, extreme male brain theory, fetal testosterone, hormone-levels, human-behavior, latent infection, male brain theory, pervasive developmental disorders, prenatal testosterone, second to fourth digit ratio, sex ratio, sex-differences, suicide attempts, Toxoplasma gondii

Mental health

Potential immunomodulatory effects of latent toxoplasmosis in humans

January 9, 2011
Flegr, J., Striz, I.
Bmc Infectious Diseases 2011; 11: Artn 274 10.1186/1471-2334-11-274
Click for abstract
Background: About 30% of the population worldwide are infected with the protozoan parasite Toxoplasma gondii. Latent toxoplasmosis has many specific behavioral and physiological effects on the human organism. Modified reactivity of the immune system has been suggested to play a key role in many of these effects. For example, the immunosuppression hypothesis explains the higher probability of the birth of male offspring observed in Toxoplasma-positive humans and mice by the protection of the (more immunogenic) male embryos against abortion. Methods: Here we searched for indices of immunosuppression in Toxoplasma-positive subjects by comparing clinical records of immunology outpatients. Results: Our cohort study showed that the male patients with latent toxoplasmosis had decreased and the Toxoplasma-positive women had increased leukocyte, NK-cell and monocyte counts in comparison with controls. The B-cell counts were reduced in both Toxoplasma-positive men and women. The difference between Toxoplasma-positive and Toxoplasma-negative subjects diminished with the decline of the specific Toxoplasma antibody titre (a proxy for the length of infection), which is consistent with the observed decreasing strength of the effect of latent toxoplasmosis on human reproduction. The prevalence of toxoplasmosis in 128 male patients was unusually low (10.9%) which contrasted with normal prevalence in 312 female patients (23.7%) and in general population Prague (20-30%). Conclusions: Latent toxoplasmosis has immunomodulatory effects in human and probably protects men against some classes of immunopathological diseases. The main limitation of the present study was the absence of the data on the immunoreactivity of immune cells subpopulations. Therefore further studies are needed to search for indices of immunosuppression in human using more specific markers.

Tagged: antibodies, behavioral-changes, communication, gender differences, gondii, hypothesis, mice, sex ratio, testosterone concentration, traffic accidents

Physical health

Modulation of immunity in mice with latent toxoplasmosis-the experimental support for the immunosuppression hypothesis of Toxoplasma-induced changes in reproduction of mice and humans

January 8, 2010
Kankova, S., Holan, V., Zajicova, A., Kodym, P., Flegr, J.
Parasitology Research 2010; 107: 1421-1427
Click for abstract
The immunosuppression hypothesis suggests that the increased sex ratio in mice and women with latent toxoplasmosis, retarded embryonic growth in the early phases of pregnancy, prolonged pregnancy of Toxoplasma-infected women, and increased prevalence of toxoplasmosis in mothers of children with Down syndrome can be explained by the presumed immunosuppressive effects of latent toxoplasmosis. Here, we searched for indices of immunosuppression in mice experimentally infected with Toxoplasma gondii. Our results showed that mice in the early phase of latent infection exhibited temporarily increased production of interleukin (IL)-12 and decreased production of IL-10. In accordance with the immunosuppression hypothesis, the mice showed decreased production of IL-2 and nitric oxide and decreased proliferation reaction (synthesis of DNA) in the mixed lymphocyte culture in the early and also in the late phases of latent toxoplasmosis. Since about 30% of the world population are latently infected by T. gondii, the toxoplasmosis-associated immunosuppression might have serious public health consequences.

Tagged: gondii, manipulation., sex ratio, strains, virulence, women

Reproduction

Topics

  • Behavior 105
  • Cognitive functions 64
  • Mental health 439
  • Morphology 6
  • Motor functions 10
  • Personality 36
  • Physical health 134
  • Reproduction 36
  • Reviews 40
  • Sensory functions 3
  • Uncategorized 2

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Recent articles

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  • The Association between Toxoplasma gondii Infection and Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis February 6, 2020

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